In the production of a usable synthetic gas by the combustion of a carbonaceous fuel mixture, the process is conducted most effectively under a high temperature and high pressure conditions. For example, for the production of a gas from a carbonaceous fuel such as particulated coal, coke, or even oil, a preferred operating temperature range of about 2,000-3,000.degree. F. is maintained at a pressure of between about 5 to 250 atmospheres. The harsh operating conditions experienced in such a process, and in particular the wide temperature variations encountered, impose a severe strain on many segments of the gasifier or reactor and associated equipment.
The invention is addressed to an improvement in the structure of a gasifier, and particularly in the quench ring and the dip tube arrangement. The latter by their functions, are exposed to the gasifier's severest temperature conditions by virtue of the hot produced gas or effluent which contacts these members as the gas passes from the reaction chamber.
With respect to the prior art, U.S. Pat. No. 4,218,423 issued on Aug. 19, 1980 in the name of Robin et al., illustrates one form of quench ring and dip tube which can be improved through use of the present arrangement. U.S. Pat. No. 4,444,726, issued on Apr. 24, 1984 in the name of Crotty et al., also illustrates a dip tube and quench ring for a reactor vessel. In the latter, a portion of the gasifier's cooling system is insulated, but does not provide an effective means to avoid or minimize the detrimental effects that could result due to the intimate contact between the hot effluent gas and the quench ring.
Among the problems encountered due to the high temperature conditions within the gasifier, is the appearance of thermal strains which often develop in the quench ring which conducts cooling water. These strains develop as a result of the ring's close proximity to the hot effluent stream, a position which necessitates cooling. The usual problems are manifested in the form of cracks and fissures which occur in parts of the quench ring, predominately in areas where sudden transitions are present. In the latter, physical and thermal strains would be magnified and ultimately result in undesired leakage of liquid coolant.